Static control problems have been recognized for many years in the electronic industry. As the miniaturization of semiconductor devices progresses, the sensitivity of these devices toward electrical fields also increases. Static electrical charges are brought about by the movement of dissimilar materials against one another. Often, a static discharge of only a few hundred volts can damage a sensitive electronic chip, and yet, static electricity in excess of 30,000 volts can be accumulated on a human body simply from walking on a carpet. The need to prevent static charge generation requires that a total assembly environment be constructed of charge dissipative materials, and that all workers and equipment be connected to electrical common ground to prevent a build-up of static charge. Thus, there is a need for products that efficiently dissipate electrical charges.
It has been discovered that by coating carbon particles (powders) onto an organic fiber and subsequently calendering them into a paper felt or incorporating them into a plastic matrix, highly conductive materials that effectively dissipate charge can be provided. The instant materials, moreover, are more conductive at lower carbon concentration than other materials that are commercially available.
The instant invention provides conductive carbon-coated fibers and materials made therefrom which have a lower carbon concentration at resistivities of 1.times.10.sup.7 ohms/square or lower using a carbon concentration of only a few percent.
Lowering carbon concentration but increasing conductivity advantageously results in a lower carbon consumption, and also provides such as carbon-filled paper which has lower slough value (a decrease in the number of particles that fall out of the paper). Lowering the particle drop rate allows this paper to be used in applications more sensitive to particle contaminates.